Digital video cameras and digital still cameras as kinds of cameras are well known. When those kinds of cameras shoot a subject, the optical system of such cameras bring rays of light corresponding to the subject to a focus at an image pickup device and change the light information into electric signals.
When camera shaking occurs in a digital video camera by, e.g., hands of the camera operator shaking, pictures taken by the camera slightly oscillate from the camera shaking. As a result, it is hard to watch the reproduced pictures of the digital video camera.
A digital still camera can not realize short exposure time because the sensitivity of the image pickup device is limited. As a result, the digital still camera goes out of focus when the camera shaking occurs. That results in the pictures taken by the digital still camera becoming blurry.
Certain cameras have a function of correcting deviation caused by a slight oscillation based on a hand of an operator holding the camera shaking or by another cause for making the camera shake.
Some methods have been proposed to detect a camera shaking, and such methods utilize devices such as angular velocity sensors, a piezoelectric gyro sensor, an acceleration sensor, and an optical detecting sensor. Another known method corrects a camera shaking by utilizing an image processing method. The most popular method for addressing camera shaking utilizes a piezoelectric gyro sensor for detecting a rotary motion of the camera body.
Furthermore, detecting methods which utilize combinations of the above devices have also been suggested.
When a camera employs a piezoelectric gyro sensor, the piezoelectric gyro sensor detects angular velocity around each axis X, Y, Z of the camera. After the detection of the angular velocity, an optical system of the camera is adjusted along each axis, a vari-angle control mechanism adjusts a variable rotation angle (vari-angle) prism, a reflection mirror in the optical system is adjusted, and an image sensing device is moved appropriately by a motor, etc. Utilizing a piezoelectric gyro sensor as an angular velocity sensor which detects the angular velocities along each of the plural axes has been commercialized in a camera.
A method for detecting angular velocity by pairs of acceleration sensors is disclosed in Japanese Laid Open Patent Application 8-101,418 and Japanese Laid Open Patent Application 05-173,219. In the methods disclosed in those documents, the angular acceleration is detected by differential amplifying an output of plural acceleration sensors.
However, the present inventor has realized that camera shaking is ascribable to rotations based on an up-and-down motion and a side-to-side motion relative to the direction of the optical axis, and based upon rotation around the optical axis. Data corresponding in all directions of the X, Y, Z axes is thereby necessary when a system carries out proper correction for camera shaking.
In Japanese Laid Open Patent Application 07-225,405, the correction of camera shaking based upon angular velocities corresponding to all axes X, Y, Z is disclosed. That document, however, does not disclose the details of the method of the correction of the camera shaking based upon the three angular velocities.
Therefore, the above-noted background art systems can not correct for camera shaking based upon rotations based on an up-and-down motion and a side-to-side motion relative to the direction of the optical axis, and based upon rotation around the optical axis.